Analysis of microplastics in water by micro-Raman spectroscopy: Release of plastic particles from different packaging into mineral water.
Level 5 - mechanism / opinion, no new human data
Bench analytical study testing consumer water products; level 5 by design analogy.
PubMed 29145085 · doi:10.1016/j.watres.2017.11.011
What was done
Researchers in Germany used micro-Raman spectroscopy to detect and characterize microplastics (<500 µm) in commercially available mineral waters. They analyzed water from 22 returnable and single-use plastic bottles, 3 beverage cartons, and 9 glass bottles, comparing particle concentrations and chemical compositions against laboratory blank controls.
What was found
Microplastic particles were detected across all packaging types, with nearly 80% measuring between 5 and 20 µm. Water in returnable plastic bottles contained an average of 118 ± 88 particles/L (predominantly 84% polyethylene terephthalate [PET] and 7% polypropylene [PP]). In contrast, single-use plastic bottles contained 14 ± 14 particles/L, beverage cartons contained 11 ± 8 particles/L, and glass bottles averaged 50 ± 52 particles/L (range: 0–253 particles/L). Compared to the procedural blank value of 14 ± 13 particles/L, only water from returnable plastic bottles showed a statistically significant elevation in microplastic content (p < 0.05).
Why it matters
This study demonstrates that micro-Raman spectroscopy captures smaller microplastic particles (5–20 µm) that are typically missed by micro-FT-IR spectroscopy. It also indicates that reusable plastic packaging and container closures can serve as a direct source of microplastic contamination in drinking water.
Limits
The sample size was small (34 containers total, with only 3 beverage cartons). Microplastic concentrations in single-use bottles and cartons were indistinguishable from procedural blanks (14 ± 13 particles/L), and the high variability observed in glass bottles (0 to 253 particles/L) highlights potential contamination or background noise challenges during testing.
Cited by
- supports Studies have found higher concentrations of microplastics in glass bottled water than in plastic bottled water due to plastic polymers in bottle cap paint shedding into the water.
- supports Studies in France and the US showed a larger volume and count of microplastics in glass bottled water compared to plastic bottled water due to paint on the metal lids.